Well, I guess it's too late to try to talk you out of expanding a case that's already on the limit of case to bore volume efficiency, huh? Or to warn you that they're a booger to fireform?
Oh well...
In that event, I'll second what Catfish said. You need to fireform with a bit faster powder. The slow, gentle pressure curve buildup that RL-22 is giving you may be super for high muzzle velocity, but it's the wrong approach to fireforming.
Look for a "book" load using a faster powder like 4895, 4064, Varget or RL-15 then load to 95% of book maximum. That should give you the pressure "pop" you need to shove brass into those real sharp corners.